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Finding the Fourth Proportional to 771.80, 1,155.30 and 747.80

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Solution

The fourth proportional to 771.80, 1,155.30 and 747.80 is: 1,119.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.80 : 1,155.30 = 747.80 : x
  2. Step 2: Convert to fraction form
    771.80/1,155.30 = 747.80/x
  3. Step 3: Cross multiply
    771.80x = 1,155.30 × 747.80
  4. Step 4: Simplify right side
    771.80x = 863,933.34
  5. Step 5: Solve for x
    x = 863,933.34/771.80
  6. Step 6: Final answer
    x = 1,119.37

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.